This invention relates generally to a biopsy apparatus and more specifically pertains to a disposable biopsy apparatus for performing a soft tissue biopsy.
It has been noted that biopsies or sampling of the inner tissue of animals and humans has become increasingly common. While there are a number of ways in which biopsies are performed, one method involves the use of two needles. One of these is a cannula or hollow needle; and the other is a stylet or needle having a recess along a portion of its length usually just behind the tip of the needle. In practice, the stylet is positioned within the cannula and the relative movements of the two needles co-ordinated to extract a tissue specimen. Thus, when the subject's skin is punctured, the recess portion of the stylet is enclosed within the cannula. Once the needles are moved to within proximity of the site from which the specimen is to be taken, the stylet is moved relative to the cannula so the recess is exposed and filled with specimen tissue. Then, the cannula is moved relative to the stylet so the cannula overcovers the recess and captures the tissue specimen. The stylet and cannula are then withdrawn, the cannula being maintained in its position covering the recess during extraction. Afterward, the cannula is pulled back from the stylet, exposing the recess, and allowing the captured tissue sample to be removed to a specimen container, or the like, for testing. The early patent to Griffith, U.S. No. 3,477,423, shows this obturator-sheath relationship.
A number of biopsy implements are known by which the above described procedure is accomplished. One such device is disclosed in the U.S. Pat. No. 4,667,684 which was invented by one of the same inventors of the present application. The device of this invention features a stylet and a cannula which are fixed at their ends to respective hubs. Both hubs are located in a guideway in the upper end of a pistol grip style hand gripping device. The device is designed for single-handed usage wherein pressing on a trigger mechanism housed in the grip results in a sequential movement of the stylet and cannula to secure a tissue specimen. A second type of implement is shown, for example, in U.S. Pat. No. 4,699,154. This device employs a series of slides and springs positioned within a box-shaped housing. A hook latch and push button release mechanism generally at the end of the device, are employed to move the stylet and cannula assemblies within the device to obtain the tissue specimen. It appears to operate just the opposite from the current invention, and incorporates dual slide bars to achieve its functioning.
While both of the biopsy devices described above, as well as others known in the art, function for their intended purpose of obtaining a biopsy sample, recent medical epidemics have imposed on the medical profession certain cautionary measures which did not have to be dealt with in the past. Of particular importance is limiting the use of needles to only one individual and, at the same time, protecting the user of the biopsy device from inadvertent exposure to potentially deadly infections. Typically this means that the biopsy device is limited to a single usage and then safely discarded. Given the number of biopsies currently being performed, there is a need for a low-cost, simple to use (preferably by one person using only one hand), instrument, which cannot accidently injure either the patient or the user, and which can readily and safely be discarded after application.
Other patents relating to this technology include the Woods U.S. Pat. No. 4,570,632, pertaining to a device in the category of cystotome for use in eye surgery. The Tesel U.S. Pat. No. 4,476,864, shows a multiple punching device for use in hair transplant. The Beraha U.S. Pat. No. 4,600,014, shows a transrectal prostate biopsy device and method. An application filed under No. A61B 10/00, under the PCT, shows a device for taking tissue sample. Another PCT application published under No. A61M 25/00, shows a wire-guide intended to be inserted into body ducts. A Soviet Union patent No. 175,611, shows an instrument for achieving puncture biopsy. A European Patent Office patent No. 0010321, shows another form of biopsy device capable of being operated with one hand. Finally, what appears to be an Austrian patent No. 141,108, shows another form of endoscopic sample excision instrument.